NONVOLATILE SEMICONDUCTOR MEMORY

摘要

PROBLEM TO BE SOLVED: To shorten a time required for a test in a nonvolatile semiconductor memory being electrically writable and erasable such as a flash memory. SOLUTION: This device is provided with a counter circuit (50) for counting the number of defects caused by write and erasure of a prescribed unit such as a sector, and a comparing circuit (51) for determining whether a value counted by the counter circuit exceeds an allowable value of the number of defects previously set. When the count value of the counter circuit exceeds the allowable value set to the register, a write operation or an erasure operation is not performed even if a command of write or erasure is inputted from the outside.